Intravascular ultrasound locating system

Abstract

An improved catheter system having intravascular ultrasound locating capabilities comprising a locator catheter and an ultrasound receiver catheter resulting in an effective electrophysiology procedure without undesired side effects of using a conventional x-ray imaging system. Said catheter system comprising a locator catheter, a reference catheter and a data acquisition computer; the locator catheter comprises at least one electrode at its distal tip section and an ultrasound crystal secured on the catheter shaft proximal to the distal end. The reference catheter comprises at least three ultrasound crystal beacons, a first ultrasound crystal beacon of said at least three ultrasound crystal beacons being located at the distal end of the reference catheter and being spaced apart from the remaining ultrasound crystal beacons, wherein the first ultrasound crystal beacon is adapted to be inserted into a vascular vessel, the reference catheter having pre-determined locations with reference to an external locating calibration system, wherein said ultrasound beacons can emit and receive ultrasound signals.

What is claimed is:  
     
       1. A catheter system for intravascular ultrasound location comprising: 
       a locator catheter comprising a catheter shaft having a distal tip section, a distal end, a proximal end and at least one lumen extending therebetween, wherein at least one electrode is secured at said distal tip section; a handle attached to the proximal end of said catheter shaft; an ultrasound crystal secured on the catheter shaft proximal to the distal end for transmitting ultrasound signals; a connector secured to the proximal end of said handle;  
       a reference catheter comprising at least three ultrasound crystal beacons for receiving the ultrasound signals transmitted from the ultrasound crystal secured to the locator catheter, a first ultrasound crystal beacon of said at least three ultrasound crystal beacons being located at the distal end of the reference catheter and being spaced apart from the remaining ultrasound crystal beacons, wherein the first ultrasound crystal beacon is adapted to be inserted into a vascular vessel; said ultrasound crystal beacons having coordinates that are pre-set with reference to an external location calibration system, and being able to emit and receive ultrasound signals; said external location calibration system for receiving signals from the crystal beacons and constantly calibrating the coordinates of the beacons on the reference catheter; and  
       a data acquisition computer connected to the location calibration system for determining the location of the locator catheter.  
     
     
       2. The catheter system of claim  1 , wherein said ultrasound crystal beacons on the reference catheter are made of piezoelectric materials. 
     
     
       3. The catheter system of claim  2 , wherein the shape of said ultrasound crystal beacons on the reference catheter is selected from the group consisting of a cylinder, a donut, a ring, a spiral, and a mesh. 
     
     
       4. The catheter system as in claim  1 , further comprising a steering mechanism at the handle for controlling the steering of the distal tip section of said locator catheter. 
     
     
       5. The catheter system of claim  4 , wherein said steering mechanism provides a plurality of deflectable curves on the distal tip section of said locator catheter. 
     
     
       6. The catheter system of claim  1 , wherein the at least one electrode is selected from the group consisting of a cylindrical tip electrode, a ring electrode, a spiral electrode, and a mesh electrode. body of a patient. 
     
     
       7. The catheter system as in claim  6 , further comprising the material of said electrode being selected from the group consisting of platinum, iridium, gold, silver, stainless steel, and Nitinol. 
     
     
       8. The catheter system as in claim  1 , wherein said reference catheter is located inside the body of a patient, wherein said reference catheter comprises a delivery shaft having a distal end, a proximal end, and at least one lumen extending therebetween; a handle attached to the proximal end of said delivery shaft; a connector secured to the proximal end of said handle; and a spiral element being located within the delivery shaft under a non-deployed state. 
     
     
       9. The catheter system as in claim  1 , further comprising a RF current generator, wherein RF current is delivered to the at least one electrode through an electrical conductor. 
     
     
       10. The catheter system as in claim  9 , further comprising a temperature sensor near the at least one electrode, wherein the catheter system is equipped with a closed-loop temperature controller, and wherein the temperature sensor is adapted for providing temperature sensing signals to the closed-loop temperature controller for controlling the RF current delivery or other suitable energy delivery. 
     
     
       11. A method for operating a catheter system to locate the catheter system about a heart, the catheter system comprising a locator catheter comprising a catheter shaft having a distal tip section, a distal end, a proximal end and at least one lumen extending therebetween, wherein at least one electrode is secured at said distal tip section; a handle attached to the proximal end of said catheter shaft; an ultrasound crystal secured on the catheter shaft proximal to the distal end; a connector secured to the proximal end of said handle; and a reference catheter comprising at least three ultrasound crystal beacons which have pre-determined locations with reference to an external locating calibration system, a first ultrasound crystal beacon of said at least three ultrasound crystal beacons being located at the distal end of the reference catheter and being spaced apart from the remaining ultrasound crystal beacons, wherein the first ultrasound crystal beacon is adapted to be inserted into a vascular vessel, wherein said ultrasound beacons can emit and receive ultrasound signals; 
       the method comprising the steps of: 
       (a) percutaneously introducing the reference catheter under non-deployed state through a blood vessel to the heart chamber;  
       (b) deploying the catheter to position the at least three ultrasound crystal beacons, and placing the first ultrasound crystal beacon within a vascular vessel;  
       (c) locating the at least three ultrasound crystal beacons in reference to an external calibration system;  
       (d) constantly calibrating the location of the crystal beacons on the reference catheter;  
       (e) percutaneously introducing the locator catheter through a blood vessel to the heart chamber;  
       (f) deflecting the distal section of said locator catheter about a transverse axis to position the tip section; and  
       (g) determining the coordinates of the locator catheter.  
     
     
       12. The method for operating a catheter system to locate the catheter system about a heart as in claim  11 , the catheter system further comprising a RF current generator, wherein radiofrequency current is delivered to a target tissue through the at least one electrode. 
     
     
       13. The method for operating a catheter system to locate the catheter system about a heart as in claim  11 , wherein said ultrasound crystal beacons on the reference catheter are made of piezoelectric materials. 
     
     
       14. The method for operating a catheter system to locate the catheter system about a heart as in claim  11 , wherein the shape of said ultrasound crystal beacons on the reference catheter is selected from the group consisting of a cylinder, a donut, a ring, a spiral, and a mesh. 
     
     
       15. The method for operating a catheter system to locate the catheter system about a heart as in claim  11 , further comprising a steering mechanism at the handle of the locator catheter for controlling the steering of the distal tip section of said locator catheter. 
     
     
       16. The method for operating a catheter system to locate the catheter system about a heart as in claim  15 , wherein said steering mechanism provides a plurality of deflectable curves on the distal tip section of said locator catheter. 
     
     
       17. The method for operating a catheter system to locate the catheter system about a heart as in claim  11 , wherein the at least one electrode is selected from the group consisting of a cylindrical tip electrode, a ring electrode, a spiral electrode, and a mesh electrode. 
     
     
       18. The method for operating a catheter system to locate the catheter system about a heart as in claim  11 , the catheter system further comprising a RF current generator, wherein RF current is delivered to the at least one electrode through an electrical conductor. 
     
     
       19. The method for operating a catheter system to locate the catheter system about a heart as in claim  18 , the catheter system further comprising a temperature sensor near the at least one electrode, wherein the catheter system is equipped with a closed-loop temperature controller, and wherein the temperature sensor is adapted for providing temperature sensing signals to the closed-loop temperature controller for controlling the RF current delivery or other suitable energy delivery.